Pre-execution is a novel latency-tolerance technique where one or more helper threads run in front of the main computation and trigger long-latency delinquent events early so that the main thread makes forward progress without experiencing stalls. The most important issue in pre-execution is how to construct effective helper threads that quickly get ahead and compute the delinquent events accurately. Since the manual construction of helper threads is error-prone and cumbersome for a programmer, automation of such an onerous task is inevitable for pre-execution to be widely used for a variety of real-world workloads. In this thesis, we study compiler-based pre-execution to construct prefetching helper threads using a source-level compiler. We first introduce various compiler algorithms to optimize the helper threads; program slicing removes noncritical code unnecessary to compute the delinquent loads, prefetch conversion reduces blocking in the helper threads by converting delinquent loads into nonblocking prefetches, and loop parallelization speculatively parallelizes the targeted code region so that more memory accesses are overlapped simultaneously. In addition to these algorithms to expedite the helper threads, we also propose several important algorithms to select the righ
